1. Field of the Invention
The present invention relates to headrest to be mounted on an upper end of a seat back of automobile and the like and a method for its production.
2. Description of the Related Art
The headrest that is vertically adjustable is mounted on an upper end of a seat back of automobile and the like to protect the head of a passenger and to secure a comfort to him.
As a method for production of such headrest, there have heretofore been two methods, (1) a method of performing an foam molding of a headrest not covered with a skin and then covering it with a skin, and (2) a method of performing a so called skin-integrated foam molding that doubles a covering of the skin in the formation of a foamed plastic unit that becomes a pillow.
With respect to the foregoing method (2) of the skin integrated foam molding, stay 92 was inserted into a stay hole 11 of the skin 1 to be protruded outside in the first place, and a base portion 91 of an insert 9 was disposed in the skin 1 to produce an assembly. Next, they were set on cavity surfaces 53 and 54 of a foaming mold 5 (FIG. 10). Thereafter, a foamed plastics material 6 was poured into the skin 1 using a funnel 8 and the like to conduct the foam molding, curing and opening of a mold whereby a desired headrest was provided.
However, the headrest produced in the conventional skin-integrated foam molding had the following problems.
As the skin 1, a laminated skin such as cloth or blow molding skin made of polyvinyl chloride or the like was used, and when the foam molding was carried out pouring the foamed plastics material 6 after disposing the base portion 91 of the insert 9 into the skin 1, due to lack of rigidity in the skin 1, the skin tended to fall out on the bottom of the cavity 55 as shown in FIG. 10 (chained line as shown in FIG. 10). Even if a stop member 99 of doughnut plate type was mounted on an opening edge 14 of the skin 1, due to a slippage of the stay 92 made of metal, the setting of the stay 92 at the predetermined positions was found difficult.
As a result, in the setting of an assembled component of the skin 1 and the insert 9 in the foaming mold 5, one of notches 921 for lifting positioning that activate the stay 92 at the upper end of the seat back was caused to engage an insert holder 57 of the foaming mold 5, and moreover, the stay 92 was lifted to expand the skin 1, and the upper portion of the skin 1 was required to abut tightly on the upper surface of the cavity 59. This work required for the man-hour of about 5 seconds/piece, and became a work burden in a mass production. Also, even if the abovementioned measure was taken, the position of the skin was not determined due to lack of a structure of engaging the skin 1 at a predetermined position. As described hereinabove, even though the foaming mold 5 was clamped after arranging the skin 1, the stay 92 protruded from the opening edge 14 of the skin 1 and a length L was fluctuated. When the protrusion occurred and the length L became longer, creases were produced on a general surface of the headrest, or when the inverse protrusion occurred and the length L became too short, creases were produced on a lower surface of the headrest.